The present invention relates generally to an apparatus useful for the repair of a damaged section of a tire. More specifically, the present invention relates to an apparatus used for vulcanizing a rubber patch that employs heat and pressure during the repair process.
Various types of apparatus have been used in the past to repair a damaged section of a tire. It is well known to use a molded section that conforms with the shape of the tire, in conjunction with an arrangement of heat pads and air bags on both the interior and exterior of the tire. The heat pads increase the temperature of a patch applied to the damaged area to the required vulcanization temperature. The air bags are employed to maintain pressure on the heat pads for the distribution of heat throughout the patch. An example of such an apparatus is described in detail in U.S. Pat. No. 4,708,608.
In another known apparatus, the molded section that conforms with the shape of the tire is replaced with a series of straps that maintain pressure on the heat pads which are in direct contact with the repair patch. The application of heat under pressure effectively vulcanizes the rubber patch in the repair area. In this apparatus, the straps surrounding the tire are connected to a chain which is connected to a crane or other holding means. The tire is suspended from the crane during the repair process. An example of such an apparatus is described in detail in U.S. Pat. No. 4,720,313.
However, prior art devices suffer from the problem of transportability of the entire apparatus. Prior art molded repair units are extremely large, heavy and expensive. One of the primary factors that prevents the prior art apparatus from being transportable is the requirement that a separate control station be used in conjunction with the repair unit. Such a control station is needed to operate the repair unit, and includes the control of electrical power, air inflation of mandrels, heat generation in the heat pads, and pressure in the system. Also, the molded shape of the apparatus limits the size of the tire that may be serviced. The sheer size of units containing external control stations makes their operation difficult and cumbersome.
Further, a serious problem persists with tire repair units that employ straps for the application of heat under pressure to the patch to be Vulcanized. Straps have proven ineffective in maintaining an evenly distributed and uniform pressure on the repair patch. Any deviation from a uniform pressure of heat will result in a malformed patch. As a result, the integrity of the patch will be seriously compromised.
No prior art apparatus has successfully provided a solution to these problems which arise during the repair of a damaged tire section. Thus, known devices fail to provide a lightweight and portable tire repair unit which enables the application of uniform pressure to assure proper vulcanization of rubber patches on a tire section to be repaired, and which can be used on a wide range of tire sizes.